Conventional technology pertaining to certain embodiments of the present invention includes:
Detonation or pre ignition typically manifests as an “explosion” or uncontrolled ignition instead of controlled burning of the fuel air mixture inside a combustion chamber. Detonation, pre ignition or “knock” is detected in car engines using a “knocking” i.e. acoustic sensor.
A piston engine has a piston that moves when pressure is applied, and valves to control intake and exhaust of contents of the cylinder. In an internal combustion engine, air and fuel are drawn inward and ignited, such that the air and fuel push on the piston trying to escape. In contrast, in a steam engine, the inlet valve opens, and steam under pressure pushes on the piston, until the exhaust valve opens to let the steam under pressure out.
According to Wikipedia, in an internal combustion engine the combustion of a fuel (normally a fossil fuel) occurs with an oxidizer (usually air) in a combustion chamber. The expansion of the high-temperature and high-pressure gases produced by combustion apply direct force to some component of the engine e.g. pistons, turbine blades, or a nozzle. This force moves the component over a distance, transforming chemical energy into useful mechanical energy. Usually combustion is intermittent, such as the four-stroke and two-stroke piston engines, the six-stroke piston engine and the Wankel rotary engine. A second class of internal combustion engines uses continuous combustion: gas turbines, jet engines and most rocket engines.
According to Wikipedia, a throttle is the mechanism by which the flow of a fluid is managed by constriction or obstruction. An engine's power can be increased or, more usually, decreased by restriction of inlet gases (e.g. by use of a throttle including any mechanism by which the power or speed of an engine is regulated). What is often termed a throttle (in an aviation context) is sometimes called a thrust lever. In a gasoline internal combustion engine, the throttle is a valve that directly regulates the amount of air entering the engine, indirectly controlling the charge (fuel+air) burned on each cycle due to the fuel-injector or carburetor maintaining a relatively constant fuel/air ratio. In a motor vehicle the control used by the driver to regulate power is sometimes called the throttle pedal or accelerator.
According to Wikipedia, the throttle valve may be controlled with a throttle pedal or lever via a direct mechanical linkage. In a reciprocating-engine aircraft, the throttle control is usually a hand-operated lever or knob. The hand-operated lever or knob controls the engine power, which may or may not result in a change of RPM, depending on propeller installation (fixed-pitch or constant speed).
According to Wikipedia, mechanisms are known to detect knocking and adjust timing or boost pressure accordingly in order to offer improved performance on high octane fuels while reducing the risk of engine damage caused by knock while running on low octane fuels. An early example of this is in turbo charged Saab H engines, where a system called Automatic Performance Control was used to reduce boost pressure if it caused the engine to knock.
According to Wikipedia, Automatic Performance Control (APC) was the first engine knock and boost control system that was introduced on turbo charged Saab H engines in 1982 and was fitted to all subsequent 900 Turbo's through 1993 (and 1994 convertibles), as well as 9000 Turbo's through 1989. The APC controls boost pressure—specifically, the rate of rise and maximum boost level—and it detects and manages harmful knock events. To control the turbocharger, the APC monitors the engine's RPM and inlet manifold pressure via a pressure transducer, and uses these inputs to control a solenoid valve that trims the rate of rise of pressure as well as the maximum pressure by directing boost pressure to the turbocharger's pneumatic waste gate actuator.
According to Wikipedia, to detect knock, a piezoelectric knock sensor (basically a microphone) bolted to the engine block responds to unique frequencies caused by engine knock. The sensor generates a small voltage that is sent to the electronic control unit, which processes the signal to determine if, in fact, knock is occurring. If it is, then the control unit activates a solenoid valve that directs boost pressure out of the turbochargers pneumatically controlled waste gate actuator, which opens the waste gate to bypass exhaust gases from the turbocharger directly to the exhaust pipe, lowering turbo boost pressure until the knock subsides. Knock events that are managed by the APC can be “seen” when the in-dash boost needle “twitches” slightly. The APC unit has a ‘knock’ output where a LED may be connected. This LED will then light up if knock is detected. The pictured APC gauge has this custom LED fitted at the end of the red scale. Because the knock sensor becomes less accurate at high revolutions, the APC tapers maximum boost pressure after approximately 4,500 RPM.
According to Wikipedia, avoidance of knocking combustion motivated a variety of simulation technologies which can identify engine design or operating conditions in which knock might be expected to occur. This then enables engineers to design ways to mitigate knocking combustion whilst maintaining a high thermal efficiency. Since the onset of knock is sensitive to the in-cylinder pressure, temperature and pre ignition chemistry associated with the local mixture compositions within the combustion chamber, simulations which account for all of these aspects have thus proven most effective in determining knock operating limits and enabling engineers to determine the most appropriate operating strategy.
SRM suite combustion software, distributed by Computational Modeling Cambridge Ltd., Sheraton House, Castle Park, Cambridge, CB3 0AX United Kingdom is said to employ “advanced combustion models specifically for the application to Spark Ignition (SI) engine combustion. These models can be used to study . . . auto-ignition chemistry leading to engine knock.”
The disclosures of all publications and patent documents mentioned in the specification, and of the publications and patent documents cited therein directly or indirectly, are hereby incorporated by reference.